linux/net/bridge/br_stp_timer.c
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   1/*
   2 *      Spanning tree protocol; timer-related code
   3 *      Linux ethernet bridge
   4 *
   5 *      Authors:
   6 *      Lennert Buytenhek               <buytenh@gnu.org>
   7 *
   8 *      This program is free software; you can redistribute it and/or
   9 *      modify it under the terms of the GNU General Public License
  10 *      as published by the Free Software Foundation; either version
  11 *      2 of the License, or (at your option) any later version.
  12 */
  13
  14#include <linux/kernel.h>
  15#include <linux/times.h>
  16
  17#include "br_private.h"
  18#include "br_private_stp.h"
  19
  20/* called under bridge lock */
  21static int br_is_designated_for_some_port(const struct net_bridge *br)
  22{
  23        struct net_bridge_port *p;
  24
  25        list_for_each_entry(p, &br->port_list, list) {
  26                if (p->state != BR_STATE_DISABLED &&
  27                    !memcmp(&p->designated_bridge, &br->bridge_id, 8))
  28                        return 1;
  29        }
  30
  31        return 0;
  32}
  33
  34static void br_hello_timer_expired(unsigned long arg)
  35{
  36        struct net_bridge *br = (struct net_bridge *)arg;
  37
  38        br_debug(br, "hello timer expired\n");
  39        spin_lock(&br->lock);
  40        if (br->dev->flags & IFF_UP) {
  41                br_config_bpdu_generation(br);
  42
  43                mod_timer(&br->hello_timer, round_jiffies(jiffies + br->hello_time));
  44        }
  45        spin_unlock(&br->lock);
  46}
  47
  48static void br_message_age_timer_expired(unsigned long arg)
  49{
  50        struct net_bridge_port *p = (struct net_bridge_port *) arg;
  51        struct net_bridge *br = p->br;
  52        const bridge_id *id = &p->designated_bridge;
  53        int was_root;
  54
  55        if (p->state == BR_STATE_DISABLED)
  56                return;
  57
  58        br_info(br, "port %u(%s) neighbor %.2x%.2x.%pM lost\n",
  59                (unsigned int) p->port_no, p->dev->name,
  60                id->prio[0], id->prio[1], &id->addr);
  61
  62        /*
  63         * According to the spec, the message age timer cannot be
  64         * running when we are the root bridge. So..  this was_root
  65         * check is redundant. I'm leaving it in for now, though.
  66         */
  67        spin_lock(&br->lock);
  68        if (p->state == BR_STATE_DISABLED)
  69                goto unlock;
  70        was_root = br_is_root_bridge(br);
  71
  72        br_become_designated_port(p);
  73        br_configuration_update(br);
  74        br_port_state_selection(br);
  75        if (br_is_root_bridge(br) && !was_root)
  76                br_become_root_bridge(br);
  77 unlock:
  78        spin_unlock(&br->lock);
  79}
  80
  81static void br_forward_delay_timer_expired(unsigned long arg)
  82{
  83        struct net_bridge_port *p = (struct net_bridge_port *) arg;
  84        struct net_bridge *br = p->br;
  85
  86        br_debug(br, "port %u(%s) forward delay timer\n",
  87                 (unsigned int) p->port_no, p->dev->name);
  88        spin_lock(&br->lock);
  89        if (p->state == BR_STATE_LISTENING) {
  90                p->state = BR_STATE_LEARNING;
  91                mod_timer(&p->forward_delay_timer,
  92                          jiffies + br->forward_delay);
  93        } else if (p->state == BR_STATE_LEARNING) {
  94                p->state = BR_STATE_FORWARDING;
  95                if (br_is_designated_for_some_port(br))
  96                        br_topology_change_detection(br);
  97                netif_carrier_on(br->dev);
  98        }
  99        br_log_state(p);
 100        br_ifinfo_notify(RTM_NEWLINK, p);
 101        spin_unlock(&br->lock);
 102}
 103
 104static void br_tcn_timer_expired(unsigned long arg)
 105{
 106        struct net_bridge *br = (struct net_bridge *) arg;
 107
 108        br_debug(br, "tcn timer expired\n");
 109        spin_lock(&br->lock);
 110        if (br->dev->flags & IFF_UP) {
 111                br_transmit_tcn(br);
 112
 113                mod_timer(&br->tcn_timer,jiffies + br->bridge_hello_time);
 114        }
 115        spin_unlock(&br->lock);
 116}
 117
 118static void br_topology_change_timer_expired(unsigned long arg)
 119{
 120        struct net_bridge *br = (struct net_bridge *) arg;
 121
 122        br_debug(br, "topo change timer expired\n");
 123        spin_lock(&br->lock);
 124        br->topology_change_detected = 0;
 125        br->topology_change = 0;
 126        spin_unlock(&br->lock);
 127}
 128
 129static void br_hold_timer_expired(unsigned long arg)
 130{
 131        struct net_bridge_port *p = (struct net_bridge_port *) arg;
 132
 133        br_debug(p->br, "port %u(%s) hold timer expired\n",
 134                 (unsigned int) p->port_no, p->dev->name);
 135
 136        spin_lock(&p->br->lock);
 137        if (p->config_pending)
 138                br_transmit_config(p);
 139        spin_unlock(&p->br->lock);
 140}
 141
 142void br_stp_timer_init(struct net_bridge *br)
 143{
 144        setup_timer(&br->hello_timer, br_hello_timer_expired,
 145                      (unsigned long) br);
 146
 147        setup_timer(&br->tcn_timer, br_tcn_timer_expired,
 148                      (unsigned long) br);
 149
 150        setup_timer(&br->topology_change_timer,
 151                      br_topology_change_timer_expired,
 152                      (unsigned long) br);
 153
 154        setup_timer(&br->gc_timer, br_fdb_cleanup, (unsigned long) br);
 155}
 156
 157void br_stp_port_timer_init(struct net_bridge_port *p)
 158{
 159        setup_timer(&p->message_age_timer, br_message_age_timer_expired,
 160                      (unsigned long) p);
 161
 162        setup_timer(&p->forward_delay_timer, br_forward_delay_timer_expired,
 163                      (unsigned long) p);
 164
 165        setup_timer(&p->hold_timer, br_hold_timer_expired,
 166                      (unsigned long) p);
 167}
 168
 169/* Report ticks left (in USER_HZ) used for API */
 170unsigned long br_timer_value(const struct timer_list *timer)
 171{
 172        return timer_pending(timer)
 173                ? jiffies_to_clock_t(timer->expires - jiffies) : 0;
 174}
 175
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